6-K

FORM 6-K

U.S. SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16 UNDER THE

SECURITIES EXCHANGE ACT OF 1934

Dated July 17, 2015

Commission File Number 1-14878

GERDAU S.A.

(Exact Name as Specified in its Charter)

N/A

(Translation of Registrant’s Name)

Av. Farrapos 1811

Porto Alegre, Rio Grande do Sul - Brazil CEP 90220-005

(Address of principal executive offices)

Indicate by check mark whether the registrant files or will file annual reports under cover Form 20-F or Form 40-F.

Form 20-F x   Form 40-F o

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1): o

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7): o

Indicate by check mark whether by furnishing the information contained in this Form, the registrant is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934.

Yes o   No x

If “Yes” is marked, indicate below the file number assigned to the registrant in connection with Rule 12g3-2(b):  Not applicable.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused the Report to be signed on its behalf by the undersigned, thereunto duly authorized.

Date:  July 17, 2015

GERDAU S.A.
By:	/s/ Harley Lorentz Scardoelli
Name:	Harley Lorentz Scardoelli
Title:	Investor Relations Director

2

EXHIBIT INDEX

Exhibit	Description of Exhibit
99.1	Notice to the Market, July 17, 2015

3

EX-99.1

Exhibit 99.1

NOTICE TO THE MARKET

The management of Gerdau S.A., in light of recent enquiries from market players and media reports regarding the transactions mentioned in the Material Fact disclosed on July 14, hereby reiterates that the Company has always been interested in concentrating the stake in its operational subsidiaries (Gerdau Açominas S.A., Gerdau Aços Longos S.A., Gerdau Aços Especiais S.A. and Gerdau América Latina Participações S.A.), even though there is no contractual obligation to carry out these acquisitions.

To avoid incorrect interpretations, based on questions received by the Company’s Investor Relations department, we emphasize that the selling shareholders of the interests acquired are Itaú Unibanco S.A. and ArcelorMittal Netherlands BV, and hence these transactions are not with the controlling shareholder or related parties.

As for the timing and value of the transaction, we affirm that the acquisitions resulted from market opportunities and, in the management’s opinion, were carried out at appropriate prices, considering the economic valuations, financial instruments used, payment terms, the value gained through a more concentrated cash flow and the Company’s long-term vision.

Porto Alegre, July 17, 2015.

Harley Lorentz Scardoelli

Investor Relations Director